The displacement $y$ of a wave travelling in the $x$ - direction is $y = 10^{-4} \sin(600t – 2x + \large\frac{\pi}{3})m$, where, $x$ is in $m$ and $t$ is in $s$. The speed of the wave motion in $m/s$ is

Question

$\begin {array} {1 1} (a)\;300 & \quad (b)\;600 \\ (c)\;1200 & \quad (d)\;200 \end {array}$